The present invention relates to methods for production of carbon black using preheated feedstock with fouling control. The present invention also relates to an apparatus for production of carbon black using preheated feedstock with fouling control. The present invention also relates to carbon black resulting from the processes of the present invention.
Carbon blacks are widely utilized, for example, as pigments in ink compositions, paints and the like, as fillers and reinforcing pigments in the compounding and preparation of rubber compositions and plastic compositions, and for a variety of other applications. Carbon blacks are generally produced in a furnace-type reactor by reacting a hydrocarbon feedstock with hot combustion gases to produce combustion products containing particulate carbon black. In the carbon black literature, this reaction between the combustion gases and the hydrocarbon feedstock is generally referred to as pyrolysis.
A variety of methods for producing carbon blacks are generally known. In one type of a carbon black furnace reactor, such as shown in U.S. Pat. No. 3,401,020 to Kester et al., or U.S. Pat. No. 2,785,964 to Pollock, a fuel, such as hydrocarbonaceous fuel, and an oxidant, such as air, are injected into a first zone and react to form hot combustion gases. A hydrocarbonaceous feedstock in either gaseous, vapor or liquid form is also injected into the first zone whereupon reaction of the hydrocarbonaceous feedstock commences. The resulting combustion gas mixture, in which the reaction is occurring, then passes into a reaction zone where completion of the carbon black forming reaction occurs. In another type of carbon black furnace reactor, a liquid or gaseous fuel is reacted with an oxidant, such as air, in the first zone to form hot combustion gases. These hot combustion gases pass from the first zone, downstream through the reactor, into a reaction zone and beyond. To produce carbon blacks, a hydrocarbonaceous feedstock is injected at one or more points into the path of the hot combustion gas stream. Generally the hydrocarbonaceous feedstock is a hydrocarbon oil or natural gas. The first (or combustion) zone and the reaction zone may be divided by a choke or zone of restricted diameter which is smaller in cross section than the combustion zone or the reaction zone. The feedstock may be injected into the path of the hot combustion gases upstream of, downstream of, and/or in the restricted diameter zone. The hydrocarbon feedstock may be introduced in atomized and/or non-atomized form, from within the combustion gas stream and/or from the exterior of the combustion gas stream. Carbon black furnace reactors of this type are shown, for example, in U.S. Reissue Pat. No. 28,974, to Morgan et al., and U.S. Pat. No. 3,922,335, to Jordan et al.
In generally known reactors and processes, the hot combustion gases are at a temperature sufficient to effect the reaction of the hydrocarbonaceous feedstock injected into the combustion gas stream. In one type of reactor, such as the above-indicated U.S. Pat. No. 3,401,020 to Kester et al., feedstock is injected, at one or more points, into the same zone where combustion gases are being formed. In other type reactors or processes, the injection of the feedstock occurs, at one or more points, after the combustion gas stream has been formed. The mixture of feedstock and combustion gases in which the reaction is occurring is sometimes hereinafter referred to, throughout the application, as “the reaction stream.” The residence time of the reaction stream in the reaction zone of the reactor is sufficient to allow the formation of desired carbon blacks. In either type of reactor, since the hot combustion gas stream is flowing downstream through the reactor, the reaction occurs as the mixture of feedstock and combustion gases passes through the reaction zone. After carbon blacks having the desired properties are formed, the temperature of the reaction stream is lowered to a temperature such that the reaction is stopped, and carbon black product can be recovered.
Other patents, such as U.S. Pat. No. 3,922,335 to Jordan et al.; U.S. Pat. No. 4,826,669 to Casperson; U.S. Pat. No. 6,348,181 to Morgan; and U.S. Pat. No. 6,926,877 to Green, also show the processes for producing carbon black, including feedstock temperatures. Typical feedstock temperatures at the point of entry to the reactor, such as shown in U.S. Pat. No. 4,826,669, can range, for example, from 250° F. to 500° F. (121° C. to 260° C.).
The present investigators have recognized that hydrocarbonaceous feedstock temperatures in carbon black production that approach or exceed about 300° C. at the point or prior to the point of entry to the reactor would create a high risk of disruptive levels of thermally induced fouling of feedstock supply lines and equipment. Further, the present investigators believe that methods and systems for producing carbon black that can tolerate such hot feedstocks have not been previously developed, nor have the possible benefits of using hot feedstock operation previously been fully realized or attainable, until the development of the present methods and arrangements for carbon black production.